Tommy Zethreaus was given a life sentence after the shootings in 1994, when he fired a gun straight into a well-known restaurant, killing a bouncer and three restaurant guests. Many others were injured in the rain of bullets and by the shattered glass.
He has also been convicted of organising other serious crimes since then from inside prison, news agency TT reports.
A local court decided today to convert his life sentence to 33 years in jail. According to Swedish praxis that means he could be released after serving two-third of that sentence, meaning he could be released in two years time.